Abstract: A method of locating a concealed conductor is performed by generating a magnetic field with a direction in which the field is a maximum. The magnetic field is rotated until that direction is directed towards the conductor. In this way, a signal is induced in the conductor which has a maximum value when that direction is directed towards the conductor. The induced signal is detected in the conductor, using a detector arranged to determine the direction of the conductor relative to the detector. The detector detects when the induced signal has the maximum value.

Abstract: In order to locate an electrically conductive object, the electromagnetic field generated by a current in the object is detected by a detector having a plurality of spaced apart antennas. In order for the location of the object to be determined, two or more of the antennas together have at least four aerials, with first and second aerials measuring field components in a direction perpendicular to the direction of separation of the antennas, the third aerial measuring field components parallel to the direction of separation and the fourth aerial measuring field components in a direction mutually perpendicular to the field components measured by the first, second and third aerials.